One cause is the North and the South, The rights between the North and the South, and the fight between the North and the South.
The North wanted to restore the union. its force had to invade the south and fore the brake away states to give up their quest for independence.
The strategies that the north use is the north would tire of the war. The south also tried to win the support of Great Britain and France
Some of the strengths of the north and the south had is, the north had a large population and more resources than the south. The south had others advantages, such as excellent millitary leader and a strong fighting spirit.